in circulation vs in season

in circulation

prep
  • Percolating between people or places. 

  • Freely available; not restricted in access; in general use. 

  • Seen in public. 

in season

prep
  • In the time for eating, using, etc. 

  • In heat 

How often have the words in circulation and in season occurred in a corpus of books? (source: Google Ngram Viewer )